Tube coupling

ABSTRACT

A slip-in type tube coupling formed of a body having a central bore whose forward end is enlarged, a centrally apertured cap fastened upon the forward end of the body, a springy grab ring having an outer flat edge portion, clamped against the body forward end by the cap, and an inner frustoconical shaped gripping portion. A U-shaped resilient sealing ring with a corresponding frustoconically shaped base receives the gripping portion in face-to-face contact, with its outer leg sealing against the wall of the enlarged portion of the bore and its inner leg sealing against the tube.

United States Patent [72] Inventor Jacob J. Hamburg 2003 West Eight MileRoad, Detroit, Mich. 48203 [211 App]. No. 91,884 [22] Filed Nov. 23,1970 [45] Patented Jan. 11, 1972 Continuation-impart of application Ser.No. 885,689, Dec. 17, 1969. This application Nov. 23, 1970, Ser. No.91,884

[54] TUBE COUPLING 5 Claims, 10 Drawing Figs.

[52] US. Cl 285/81, 285/93, 285/1 1 1, 285/340, 285/354 [51] Int. ClF161 17/02 [50] Field ot'Search 285/340, 81,111,110, 93, 354, 386;151/9, 28,11

[56] References Cited UNITED STATES PATENTS 3,468,564 9/1969 Frohlieh285/111 3,291,510 12/1966 Kody 285/340 3,362,729 1/1968 Hendriks 285/340X 3,409,319 11/1968 Vanl-leeke 151/11 X Primary ExaminerThomas F.Callaghan Attorney-Cullen, Settle, Sloman & Cantor ABSTRACT: A slip-intype tube coupling formed of a body having a central bore whose forwardend is enlarged, a centrally apertured cap fastened upon the forward endof the body, a springy grab ring having an outer flat edge portion,clamped against the body forward end by the cap, and an innerfrustoconical shaped gripping portion. A U-shaped resilient sealing ringwith a corresponding frustoconically shaped base receives the grippingportion in face-to-face contact, with its outer leg sealing against thewall of the enlarged portion of the bore and its inner leg sealingagainst the tube.

PATENTED JAN] 1 I972 33; 944

sum 2 BF 2 9 23 44! 43 b 34 T9 was J Q s All FIGB INVENTOR ".mcoe J.HAMBURG ATTORNEYS TUBE COUPLING PARENT APPLICATION This application is acontinuation-in-part of my earlier application Ser. No. 885,689 filedDec. 17, 1969.

BACKGROUND OF INVENTION The invention herein relates to slip-in typecouplings for receiving and coupling a smooth, thin wall metal orplastic tube to some other type of fixture or pipe. conventionally, thistype of coupling has consisted of a centrally bored tube receiving bodycontaining a frustoconical shaped springy grab ring whose inner, annularedge grips and bites into the outer wall of the tube.

Usually, such couplings have included an apertured cap, through whichthe tube is inserted to enter the body, with the cap functioning to holdthe grab ring in position within the body as well as to apply an axialforce for compressing suitable sealing rings against the outer wall ofthe tube for preventing fluid leakage through the coupling. In this typedevice, it was necessary to loosen the cap in order to expand or relaxthe sealing ring or rings for receiving the tube, after which the caphad to be tightened for compressing the sealing rings and causing thegrab ring to grip the tube against withdrawal.

An example of this prior type of tube coupling is illustrated in US.Pat. No. 3,312,484 to Davenport, granted Apr. 4, 1967. In the couplingillustrated, for example, in said patent, it was necessary to tightenthe cap sufficiently to tightly compress the sealing ring inwardlyagainst the tube, after insertion of the tube, in order to preventleakage of fluid through the coupling. In addition to forming arelatively inefficient or poor seal, generally unsuitable forhigh-pressure fluid flow, the inward compression of the sealing ringstended to buckle or bend inwardly the thin wall of the tube.

Thus, the invention herein relates to an improvement in slip-in tubecouplings of the type illustrated by way of example in the foregoingpatent.

SUMMARY OF INVENTION The invention herein generally contemplatespositioning a U-shaped sealing ring within an enlarged forward endportion of the coupling body bore, with the base of the ring beingfrustoconical in shape to mate with or correspond with the frustoconicalshape of the grab ring which is received therein in face-to-facecontact, with the outer leg of the sealing ring sealed against the walldefining the bore and the inner leg sealing against the tube receivedwithin the body bore. The end cap squeezes the grab ring against the endof the coupling body for frictionally holding it in place. Thus, the capis not loosened at any time, even for insertion of the tube, but ratheronce assembled, prior to insertion of the tube, remains static and isremoved only for purposes of disengaging the tube from the couplingbody. Under high pressure force, the U-shaped sealing ring not onlyapplies greater inward pressure to seal against the tube, but alsoforces the frustoconical shaped grab ring into tighter engagement withthe tube to prevent withdrawal thereof as well as fluid leakage aroundthe outside of the tube.

The invention herein also contemplates the addition of an annular lip onthe interior of the cap to serve as a stop means for preventing thefrustoconical grab ring from bending reversely upon an outwardwithdrawal movement of the tube, thereby preventing tube withdrawalexcept when the cap is removed. In addition, cooperating contacts areprovided on the cap and coupling body to audibly signal at the pointthat the cap is properly tightened upon the body to thereby preventovertightening of the cap.

These and other objects and advantages of this invention will becomeapparent upon reading the following description, of which the attacheddrawings form a part.

DESCRIPTION OF DRAWINGS FIG. 1 illustrates a cross-sectional,elevational view of the tube coupling herein with the end of the tubepositioned within the coupling.

FIG. 2 is a reduced scale, perspective view of the cap, per se.

FIG. 3 is an elevational view, partially in cross section, of thevarious parts making up the coupling in disassembled relationship.

FIG. 4 is a plan view of the assembled coupling.

FIG. 5 is a cross-sectional, elevational view of a modified coupling,and

FIGS. 6 and 7 are enlarged fragmentary views showing the sealing ringrespectively before and after insertion of a tube.

FIG. 8 shows the coupling of FIG. 5 with the parts disassembled.

FIG. 9 is a plan view taken in the direction of arrows 9-9 of FIG. 5.

FIG. 10 is an end view of the cap drawn to a reduced scale, taken in thedirection of arrows 10-10 of FIG. 8.

DETAILED DESCRIPTION The tube coupling 10 is arranged to couple a thinwall, smooth surfaced, plastic or metal tube 11 to another tube or pipeor fitting (not shown). The coupling comprises four basic elements (seeFIG. 3), namely, a centrally bored body 12, a U- shaped in cross sectionsealing ring 13, a thin springy sheet metal grab ring 14, and acup-shaped cap 15. Preferably, the body and cap are molded out of asuitable plastic material and the sealing ring is made of a rubber orsynthetic rubberlike plastic material.

The body 12 is provided with a stepped bore having a rear bore portion17, which is approximately equal to the interior diameter of the tube11, an intermediate bore portion 18, which forms a shoulder or stop forthe tube end, an outwardly tapering bore portion 19, and a forward,enlarged bore portion 20.

The body 12 is generally cylindrical in shape with an outer rearthreaded area 21 for threadedly coupling to a conventional fitting orpipe. The central portion of the body is form ed as a wrench grippingportion 22 and the forward end of the body is formed as a forwardthreaded portion 23 for threaded engagement with threads 24 formedwithin the cap 15.

The outer surface of the cap is formed with wrench gripping beads 25 forgrasping and twisting the cap upon the body for assembly.

The grab ring 14 is formed with an outer, flat, annular flange 27 whichis squeezed between the forward end of the body and the base of the capfor holding the grab ring in position. The center of the grab ring isbent into a rearwardly extending, frustoconical portion 28 havingradially extending slits 29 for increased flexibility. Its inner,annular edge defines a sharp tube gripping edge 30.

The forwardly facing surface of the base of the sealing ring is formedinto a corresponding or mating frustoconical portion 31 which receivesthe grab ring frustoconical portion in faceto-face contact. The outerleg 32 of the sealing ring is arranged in face-to-face contact with thewall defining the enlarged bore portion 20 and the inner leg 33 isarranged to contact the tube 11 in face-to-face relationship.

The four basic parts making up the coupling are assembled together, asshown in FIG. 1, with the cap 15 tightened upon the body for holding thegrab ring in position.

To prevent overtightening of the cap, one of the beads 25a is enlargedto extend rearwardly a short distance and interfere with or bump againsta short, forwardly extending projection 34 formed integral with the bodyportion 22 (see FIG. 4), when the cap is almost, but not completely,tightened. A further twist on the cap causes the projection and beadextension to resiliently spring away from each other slightly, enough tocause them to pass from the dotted line position to the solid lineposition shown in FIG. 4, where the cap is fully tightened.

As they pass each other, an audible click occurs which signals that thecap is fully tightened. This prevents stripping the threads of the capand body, which are preferably formed of a slightly resilient plasticmaterial.

In use, the tube 1 l is slipped through the central aperture 35 in-thecap 15, through the grab ring 14 and seal 13, until its end bottoms inthe intermediate bore portion 18. In this position, the annular grabring gripping edge 30 grips against and bites into the tube'to preventwithdrawal, which can be accomplished only by removing the cap 15 fordisengaging the grab ring from the tube.

Once the tube is inserted in the coupling, fluid leaking into theenlarged bore portion of the body causes the legs of the seal toseparate so that the outer leg presses even more tightly against thebore wall and the inner leg presses even more tightly against the tube,thereby increasing the sealing force in response to any increase inpressure of the fluid attempting to leak around the tube.

In addition, the base of the seal applies a pressure, in response tofluid, against the frustoconical portion of the grab ring, therebyincreasing its force of gripping against the tube and increasing it inresponse to increased fluid pressure. As can be seen, the greater thepressure of the fluid, the greater the sealing and gripping of the tubeagainst withdrawal.

In order to prevent accidental withdrawal of the tube 11, such as due toan outwardly directed force applied to the tube, wherein tube withdrawalmovement has a tendency to cause the grab ring frustoconical portion tobend reversely, a stop or antireversing annular lip 36 is formed aroundthe opening 35 on the interior of the cap. The lip is normally spacedfrom the grab ring as shown in FIG. 1. However, as the grab ring bucklesor tends to bend reversely due to a pull on the tube, it contacts thelip 36 which stops it against any further buckling or reversing, therebypreventing withdrawal of the tube.

An outer, annular flange 37 surrounding the outer end of the cap opening35 increases the support and positioning of the tube 11 within thecoupling.

MODIFICATION-FIGS. -10

FIGS. 5-10 illustrate a modification wherein the inner bore 18a of thebody 12a is forwardly elongated and terminates in a wedgelike, annularflange 40 which fits between the legs 41-42 of an elongated, resilientU-shaped seal ring 43. The outer ring leg 41 fits into, but is spacedfrom the bottom of, a slightly tapered groove 44 formed between flange40 and forward bore portion 45.

As shown in FIG. 6, the outer ring leg 41 is slightly squeezed withinthe groove 44. The inner ring leg is curved or bent radially inwardly bythe flange 40. When tube 11 is inserted into the coupling, the innerring leg 42 is squeezed or compressed between the flange 40 and the tubesurface, as illustrated in FIG. 7. Nevertheless, any leakage ofpressurized fluid within the coupling tends to pass between the flange40 and into the space between seal legs 41-42 causing them to moretightly seal against the tube 1 1 and the surface of bore portion 45.

Also, the flange 40, tends to center the seal within the bore andprevent it from shifting or buckling during assembly and during tubeinsertion.

The cap 15 is provided with annular flange bead 46 and a number of bumpsor projections 47, corresponding to each of the wrench beads 25. Whenthe cap is threaded upon the body, the first of the bumps to strike andpass over the body projection 34 (see dotted lines in FIG. 9) causes anaudible click which signals that the cap is sufficiently tightened. Thisprevents overtightening and possible damage to the parts.

Having fully described an operative embodiment of this invention, I nowclaim:

1. A tube coupling comprising a centrally bored body having a rear endand a forward end into which a tube may be received, with the forwardend portion of the bore being of greater diameter than the rear endportion;

a cup-shaped cap removably fastened to the forward end portion of thebody and having a centrally apertured base covering the body forwardend;

a grab ring formed of thin springy sheet metal shaped as a flat outerflange, clamped between the cap base and body forward end, and with anintegral, central frustoconical rearwardly extending portion whose innerfree edge defines an annular tube gripping edge;

a U-shaped in cross section resilient sealing ring having an outer legin face-to-face contact with the wall defining the bore forward endportion of said body, an inner leg normally arranged to surround andcontact the tube in faceto-face contact, and a base having its forwardface arranged in contact with the grab ring;

said body further including a forwardly extending annular flange formedhomogeneously with said body and surrounding the forward edge of thesmaller diameter rear end portion of the bore and extending a shortdistance into the greater diameter forward end portion of the bore, tothereby define an annular groove between the flange and the walldefining the greater diameter bore portion at the rear base thereof;

said flange being wedge-shaped in cross section and extending a shortdistance forwardly between the legs of the sealing ring to spread thefree ends of said legs apart slightly, wherein the free end portion ofthe outer leg is fitted within said groove, and the free end portion ofthe inner leg is normally arranged between and slightly compressed bythe flange and said tube;

whereby a tube may be slipped through the cap base aperture, grab ringand sealing ring to the bore rear end portion for being gripped by saidgrab ring gripping edge, and so that fluid pressure caused by leakingfluid entering the bore forward end portion forces the sealing ring tubelegs apart into tighter contact with the tube and bore wall and tends toforce the sealing ring base more tightly against the grab ring so thatits frustoconical portion tends to more tightly grip the tube, with saidbody flange maintaining said sealing ring in concentric position andholding it against twisting and buckling, as well as backing the innerleg against the tube.

2. A tube coupling as defined in claim 1, and said groove being deeperin the axial direction than the end portion of the outer leg which isfitted into said groove to form an annular space between the base of thegroove and the free end of the outer leg.

3. A tube coupling as defined in claim 1, and including the forward faceof the base of the sealing ring being formed in a frustoconical shapecorresponding to and receiving in face-toface contact the frustoconicalportion of the grab ring.

4. A tube coupling as defined in claim 1, and said cap being threadedlyconnected to threads formed upon said body;

said cap having a short axially rearwardly directed projection formedupon its rear end near the periphery thereof and arranged in the path ofa short axially forwardly directed projection formed on the body forwardend for interference contact therewith when the cap is almost tightenedupon the body, and said projections being forcibly movable relative toand past each other, for forcing one past the other to the finaltightened position of the cap relative to the body, and therebyproducing an audible sound as they pass each other, the first occurrenceof such sound signalling that the final tightened position of the caphas been reached, to thereby prevent overtightening of the cap.

5. In a tube coupling having a centrally bored body having a forward endand a rear end for receiving a tube to be coupled therein and havingmeans within the bore for gripping and securing the tube within thebore, and a cup-shaped cap having internal threads for receiving andthreadedly engaging with corresponding threads formed upon the forwardend portion of the body, with the cap being centrally apertured toreceive a tube inserted into said bore, the improvement comprising:

almost at its final tightened location upon the body, and with theprojections producing an audible sound as one is forced over and passesthe other, the first occurrence of such sound providing an audiblesignal that the cap has reached the point of final tightened locationupon the body.

1. A tube coupling comprising a centrally bored body having a rear endand a forward end into which a tube may be received, with the forwardend portion of the bore being of greater diameter than the rear endportion; a cup-shaped cap removably fastened to the forward end portionof the body and having a centrally apertured base covering the bodyforward end; a grab ring formed of thin springy sheet metal shaped as aflat outer flange, clamped between the cap base and body forward end,and with an integral, central frustoconical rearwardly extending portionwhose inner free edge defines an annular tube gripping edge; a U-shapedin cross section resilient sealing ring having an outer leg inface-to-face contact with the wall defining the bore forward end portionof said body, an inner leg normally arranged to surround and contact thetube in face-to-face contact, and a base having its forward facearranged in contact with the grab ring; said body further including aforwardly extending annular flange formed homogeneously with said bodyand surrounding the forward edge of the smaller diameter rear endportion of the bore and extending a short distance into the greaterdiameter forward end portion of the bore, to thereby define an annulargroove between the flange and the wall defining the greater diameterbore portion at the rear base thereof; said flange being wedge-shaped incross section and extending a short distance forwardly between the legsof the sealing ring to spread the free ends of said legs apart slightly,wherein the free end portion of the outer leg is fitted within saidgroove, and the free end portion of the inner leg is normally arrangedbetween and slightly compressed by the flange and said tube; whereby atube may be slipped through the cap base aperture, grab ring and sealingring to the bore rear end portion for being gripped by said grab ringgripping edge, and so that fluid pressure caused by leaking fluidentering the bore forward end portion forces the sealing ring tube legsapart into tighter contact with the tube and bore wall and tends toforce the sealing ring base more tightly against the grab ring so thatits frustoconical portion tends to more tightly grip the tube, with saidbody flange maintaining said sealing ring in concentric position andholding it against twisting and buckling, as well as backing the innerleg against the tube.
 2. A tube coupling as defined in claim 1, and saidgroove being deeper in the axial direction than the end portion of theouter leg which is fitted into said groove to form an annular spacebetween the base of the groove and the free end of the outer leg.
 3. Atube coupling as defined in claim 1, and including the forward face ofthe base of the sealing ring being formed in a frustoconical shapecorresponding to and receiving in face-to-face contact the frustoconicalportion of the grab ring.
 4. A tube coupling as defined in claim 1, andsaid cap being threadedly connected to threads formed upon said body;said cap having a short axially rearwardly directed projection formedupon its rear end near tHe periphery thereof and arranged in the path ofa short axially forwardly directed projection formed on the body forwardend for interference contact therewith when the cap is almost tightenedupon the body, and said projections being forcibly movable relative toand past each other, for forcing one past the other to the finaltightened position of the cap relative to the body, and therebyproducing an audible sound as they pass each other, the first occurrenceof such sound signalling that the final tightened position of the caphas been reached, to thereby prevent overtightening of the cap.
 5. In atube coupling having a centrally bored body having a forward end and arear end for receiving a tube to be coupled therein and having meanswithin the bore for gripping and securing the tube within the bore, anda cup-shaped cap having internal threads for receiving and threadedlyengaging with corresponding threads formed upon the forward end portionof the body, with the cap being centrally apertured to receive a tubeinserted into said bore, the improvement comprising: a fixed axiallyforwardly extending, short projection formed homogeneously on theforward end of the body and a series of circumferentially spaced apartaxially rearwardly extending projections formed homogeneously on therear end of the cap, with the projections arranged in the same rotativepath so one of said series strikes the fixed projection upon rotation ofthe cap to the point where the cap is almost at its final tightenedlocation upon the body, and with the projections producing an audiblesound as one is forced over and passes the other, the first occurrenceof such sound providing an audible signal that the cap has reached thepoint of final tightened location upon the body.